Hi Ingemar!
I looked at the web sites you found, and I agree there are some
disparities there, although it may be just the reporting dates. The
SCLF site refers to data from 1996, when most monitors were CRTs. If
the Tin (primarily used for interconnects) content was about 1% of the
total weight, and the solder used for interconnects was 63/37, then
there should have only been 0.6% of Lead by weight, not the 6% reported.
The difference might be the shielding of the CRTs, which is noted in
the data as one of the uses, although 1.5kg of Lead in a CRT sounds
high, I have no idea what this number actually is.
The second site, recycleworks, explains how they recycle the lead in
the CRT glass, but it sounds pretty new, so that may be why the Lead
recycling percentage is so low from the first website. Even the %
"recycling efficiency" works out for this scenario, since 70%(reported
efficiency for Tin) of 0.6% is about 5%(reported efficiency for Lead) of
6.3%.
The third site you provided does not have "CRT" or even "tube" anywhere
in it. Kind of looks like the authors missed a big source of lead use,
primarily focusing on batteries, which are the easiest to recycle by
far.
Wayne Thayer
>>> [log in to unmask] 12/18/2006 4:23:12 am >>>
Hi all,
This time it seems as the article is not so old as the one I used some
weeks ago.
Now, the Lead amount and recycling efficiency is little different, but
still disadvantageous compared to Tin, Copper, Gold and others. Still,
I
can't understand how one can recycle 70% of the Tin from the soldered
boards, while only 5% of the Lead, in one and the same recycling
process.
http://www.sclf.ca/hazards.php
http://www.recycleworks.org/ewaste/ewaste_process.html
According to the below link, the (general) Lead recycling efficiency
is
95% !!
http://pubs.usgs.gov/of/2001/of01-170/of01-170.pdf
Do the green organisations present statistics? I still doubt....
Inge
SMW
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